Build a multi-stage group-sequential multi-arm clinical trial for a normally distributed primary outcome

build_gs_norm() builds a multi-stage group-sequential multi-arm clinical trial design object assuming the primary outcome variable is normally distributed, like those returned by des_gs_norm.

build_gs_norm(
  n1 = 162,
  n10 = 54,
  e = c(2.42, 2.42),
  f = c(-2.42, 2.42),
  K = 2,
  alpha = 0.025,
  beta = 0.1,
  delta1 = 0.5,
  delta0 = 0,
  sigma = 1,
  ratio = 1,
  power = "marginal",
  stopping = "simultaneous",
  type = "variable",
  summary = FALSE
)

Arguments

n1	A numeric indicating the chosen value for n1, the total sample size required in stage one of the trial. Defaults to 162.
n10	A numeric indicating the chosen value for n10, the sample size required in the control arm in stage one of the trial. Defaults to 54.
e	A numeric vector indicating the chosen value for e, the efficacy (upper) stopping boundaries. Defaults to c(2.42, 2.42).
f	A numeric vector indicating the chosen value for f, the futility (lower) stopping boundaries. Defaults to c(-2.42, 2.42).
K	A numeric indicating the chosen value for K, the (initial) number of experimental treatment arms. Defaults to 2.
alpha	A numeric indicating the chosen value for α, the significance level (family-wise error-rate). Defaults to 0.025.
beta	A numeric indicating the chosen value for β, used in the definition of the desired power. Defaults to 0.1.
delta1	A numeric indicating the chosen value for δ1, the 'interesting' treatment effect. Defaults to 0.5.
delta0	A numeric indicating the chosen value for δ0, the 'uninteresting' treatment effect. Defaults to 0.
sigma	A numeric vector indicating the chosen values for σ0 and σ1, the standard deviations of the responses in the control and experimental arms. Must be of length 1 or 2. If of length 1, it is assumed that σ0 =σ1. Defaults to 1.
ratio	A numeric indicating the chosen value for r, the stage-wise allocation ratio to present experimental arms. Defaults to 1.
power	A character string indicating the chosen type of power to design the trial for. Can be "disjunctive" or "marginal". Defaults to "marginal".
stopping	A character string indicating the chosen type of stopping rule. Can be "separate" or "simultaneous". Defaults to "simultaneous".
type	A character string indicating the choice for the stage-wise sample size. Can be "variable" or "fixed". Defaults to "variable".
summary	A logical variable indicating whether a summary of the function's progress should be printed to the console. Defaults to FALSE.

Value

A list, with additional class "multiarm_des_gs_norm", containing the following elements:

• A tibble in the slot $opchar summarising the operating characteristics of the identified design.

• A tibble in the slot $pmf_N summarising the probability mass function of the random required sample size under key scenarios.

• A numeric in the slot $maxN specifying max N, the trial's maximum required sample size.

• A numeric in the slot $n_factor, for internal use in other functions.

• Each of the input variables.

See also

des_gs_norm, gui, opchar_gs_norm, plot.multiarm_des_gs_norm, sim_gs_norm.

Examples

# The design for the default parameters
des <- build_gs_norm()